Spraying apparatus



May 24, 1932- w. A. READY SPRAYING' APPARATUS Original Filed Feb. lO, 1928 Patented May 24, 1932 PATENT GFFIC WILLIAM A. READY, OF BROOKLINE, MASSACHUSETTS SPRA'YING APPARATUS Original application filed February 10, 1928, Serial No. 253,394. Divided and this application led October My invention aims to provide improve-l ments in spraying apparatus and more particularly to improvements in paint and like material spraying systems. This application is a division of my copending application Serial No. 253,394, filed February l0, 1928.

In the drawings, which illustrate preferred embodiments of my invention Figure l is a diagrammatic view of a spray system which is provided with a main switch, by which the blower may be started and stopped, a mercury switch operated by the draft from the blower and solenoid means l5 for operating the valve in the air conduit to provide a completely electrically controlled system;

Fig. 2 is a diagrammatic view of a portion of the system shown in Fig. 1, illustrating the mercury switch in operation for completing the circuit to the solenoid and showing the valve opened by the solenoid;

Fig. 3 is a diagrammatic illustration of a paint-spraying system which includes a solenoid operated damper and a switch associated therewith for making and breaking a circuit with a solenoid for operation of the valve in the air line;

Fig. 4 is a section on the line i-l of Fig. 3, showing the valve and the solenoid; and

Fig. 5 is a section on the line 5 5 of Fig. 3, showing the liuc damper and Vthe associated solenoid and' switch.

Referring to the drawings, I have illustrated in a more or less general and diagrammatic manner the important features of my invention. In each of the embodiments of my invention illustrated, I have shown apparatus which is particularly, though not 4-0 exclusively, useful in connection with spraying paint, varnish and the like upon various articles to be coated. In each of the illustrated embodiments, I section, a hood or booth l in which the article to be sprayed may be located and a suitable spray gun 2 to spray fluid upon the article to be sprayed. For the purposes of illustration, I have shown a spray gun 2 having a Vconduit connection 5 which may be connected to a 0 paint supply in the usual manner well-known have shown, in cross- Serial No. 314,925.

to those skilled in the art. A second connection d is shown with a conduit 5 connecting a fluid pressure supply (not shown) to the gun. This fluid pressure is usually compressed air which forces the paint or like material from the gun in a spray. I have also shown a iiue 6 connected to the hood or booth 1 through which gases and vapors are eX- hausted. A blower 7 is located in a proper position to create a circulation of air passing through the open side of the booth and carry the obnoxious odors and gases, which arise from the spraying means, out through the flue 6. The flue may or may not be provided with the damper 8 as desired.

I-Ieretofore, in the spraying systems of the type 'above described, the air supplyV was connected tothe spray gun in such a manner that a person need merely to release the valve in the spray gun and the material to be sprayed wouldbe ejected from the gun. The blower was operated from a switch, but if the operator forgot to turn the switch the Ventilating means would not be in operation while he was spraying articles. Many of the fluids used in spraying give olf poisonous gases or fumes and in many instances operators have been overcome and been seriously ill, because they forgot to set the blower in operation before beginning to operate the spray gun.

It is dangerous tc spray in a hood or booth located in a factory room when other employees are at work without positive operation of the Ventilating syste-m, as the other employees are also subjected to the gases and fumes which rebound from the hood or booth. Serious and costly explosions have resulted from filling a room with explosive gases created by spraying when the ventilating system was not in operation.

' In order to preventA such accidents, I have provided various methods and mechanisms for controlling the air supply to the spray g gun. These mechanisms are so constructed and arranged (as will be more fully hereinafter described) that .the Ventilating systems must be in operation when the valve means in the air conduit is open to permit the passage of compressed air to the spray gun.

In Figs. 1 and 2, I have illustrated a completely electrically operated system for controlling the opening and closing of the valve 9. Associated with the flue 6 is a mercury switch device comprising a tube 24 having one end opening into the side wall of the flue 6. The other end is located inside of the fiue in the path of the draft from the blower. The last mentioned end is in the form of a funnel 25 having its open end facing away from the blower.

The handle 14 of the valve 9 is connected to a solenoid 26 (Figs. 1 and 2) and a spring 27 normally acts upon the handle 14 to hold the valve in closed position, as shown in Fig'. 8. A main switch 28 is provided in the blower circuit.

Before paint or the like can be sprayed from the spray gun 2, shown in Fig. 1, the main switch 28 must be operated to close the blower circuit. When the blower is in operation, it creates a draft in the flue 6 in the direction of the arrows and as the air currents pass by the funnel 25 a suction is created in the tube 24. This suction, assisted by the pressure of air passing into the end of the tube connected to the flue, will act to raise the mercury (or other suitable electrical conductive fluid) in the sloping part of the tube, so as to make an electrical connection between the ends 29, 29 of the wire connected to the tube 24. lVhen this circuit is closed, in the manner just described, the solenoid will operate to turn the valve from the position shown in Fig. 1 to the position shown in Fig. 2. Thus, the valve 9 is opened and air under pressure may pass to the spray gun to permit operation thereof.

This system just described in connection with Figs. 1 and 2 is entirely automatic in its control of the air supply to the spray gun. Once the main switch 28 is operated to close the circuit to the blower the system will be ready for operation. If, however, the elect-ric current should fail, the blower 7 would stop and the mercury would recede from the ends 29, 29 connected to the tube 24, thereby breaking the solenoid circuit and the spring 27 would close the valve 9 and stop the flow of compressed air to the spray gun.

In F igs. 3 through 5, I have illustrated a system which is very similar to the one shown and described in connection with Figs. 1 and 2. In this instance, I have shown in addition a damper 8 in the flue 6 and a solenoid 30 and switch 31 connected to the damper 8. l

Vhen the main switch 28 is operated to close the blower circuit, the solenoid 30 is energized and turns the damper 8 assisted by the draft of air from the blower 7 The contact point 32 is pulled against the points 33, 33 to close the circuit to the solenoid 26, which in turn operates the valve 9 in the same manner as above described in connection with Figs. 8 and 9.

This system of control is completely elecspray gun 2 into the hood or booth from the open side thereof, so that the circulation of air through the open side carries the gases away from the operator and out through the iiue 6. The cooperation between the air pressure for operation of the spray gun 2 and the Ventilating means is such that the operator must perform some act which will set the Ventilating system in operation before paint can be sprayed and so long as paint may be sprayed the blower system will remain in operation.

While I have illustrated and described my particular invention, I do not wish to be limited thereby and therefore reference is made to the following claims to indicate the scope of my invention.

I claim:

1. In a fluid spraying apparatus of the class illustrated and described, a blower, a spray gun, a fluid pressure conveying conduit connected to said gun, a valve in said conduit and combined draft operated and electrically operated means operatively connected between the blower and the valve whereby the valve is opened only after the blower is placed in operation.

2. In a fluid spraying apparatus of the class illustrated and described, a blower, an air actuated mercury switch operable by a draft created by said blower, a fluid pressure conveying conduit, a valve in said conduit, and a solenoid operatively connected to said valve and to said mercury switch whereby said valve may be automatically opened and cle-sed by the action of said mercury switch.

3. In a fluid spraying apparatus of the class illustrated and described, a blower, a spray gun, a fluid pressure conveying conduit connected to said gun, a valve in said conduit and electrically operated means connected between the blower and the valve whereby the valve can be opened only after the blower has been placed in operation.

4. In apparatus of the class described,

spraying means which when in operation gives off a gas, Ventilating means associated with the said spraying means for conducting away the said gas, a valve in the spraying means, a draft-creating device in the ventilating means, a solenoid connected to said valve icc and a draft-operated switch whereby when the draft creating device is in operation the switch will be closed to operate the solenoid which in turn opens the valve to permit operation of the spraying means.

5. In apparatus of the class described, spraying means which when in operation gives off a gas, Ventilating means associated with the said spraying means for conducting away the said gas, a Valve in the spraying means, a draft-creating device in the Ventilating means, a solenoid connected to said Valve and an electric switch device connected V in an electric circuit with the solenoid and operable to close the electric circuit and thereby permit operation of the solenoid to open the said valve only when the draft-creating device is also in operation.

6. In apparatus of the class described, spraying means which when in operation gives off a gas or Vapor, Ventilating means associated wi-th said spraying means for conducting away the said gas or Vapor, a Valve associated with the spraying means, a draftcreating device associated with the Ventilating means and electrically operative means connected between the Valve and the draft-creating device and operable to open the Valve only upon a draft being created in said Ventilating means by said draft-creating device.

In testimony whereof, I have signed my name to this specification.

WILLIAM A. READY. 

